Currently, GPS (Global Position System) has been widely applied in civil and professional fields. In addition to self-positioning by GPS, it is widely applied that GPS information is uploaded to a processing center via a wireless communication system so as to implement GIS (Global Information System).
Conventionally, GPS information is generally uploaded by data service of a public mobile communication network such as GPRS (General Packet Radio Service). However, in some special applications, it is unreliable to upload GPS information over the public mobile communications network due to problems such as resource guarantee, coverage of mobile signals of the public network in special areas and information security. Accordingly, GPS information is uploaded by a private network for many professional users having high demands.
A cluster system is a most representative technical system for private network communication technology. Currently, there are mainly two methods as follows for acquiring terminal location information for the cluster system.
1. A Manner of Control Channel Random Access
In this method, time interval for sending the GPS information is pre-configured for a mobile station which is to upload the GPS information. The mobile station sends the GPS information to the cluster system using a random access process at the configured time interval by way of short message or other dedicate control channel data service. Therefore, the GPS information of the mobile station is acquired by the cluster system.
This method is an ideal implementation in a case that the number of mobile stations belonging to one base station is small. However, in case of a larger number of mobile stations, there is generally a high probability that other service call is initiated over the control channel. Thus the control channel may be busy, and load of the control channel may be further increased due to the GPS information transmission service. Voice call service having a higher priority may be affected significantly, call connection speed may be reduced, and even a success rate for establishing a call may be affected. Moreover, since the GPS information is uploaded in a random access manner, there may be a certain percentage of call collision when the call is busy, and efficiency for uploading the GPS information is affected.
2. A Manner of a Dedicate Data Service Channel
In this method, multiple mobile stations are taken as a mobile station group, which sends data to the cluster system over the dedicate service data channel in a period of time in a manner of a service channel random access or according to a request from the cluster system. After the sending is completed, the mobile station group automatically returns to an idle state and monitors the control channel.
Compared with the manner of control channel random access according to the first method, the manner of the dedicate service data channel has some advantages in a case of a larger number of mobile stations and a relative rich service channel resource. However, in a case of a small number of mobile stations, utilization rate of the dedicate service data channel is low, and some calls to the mobile station group may fail.